1. Field of the Invention
This invention relates to a cooling package for a construction machine such as a hydraulic excavator, and more particularly to a cover structure for a cooling package having a structure wherein a cooler from among coolers such as a radiator and an oil cooler is placed separately from an engine and a screen is provided for the separately placed cooler.
2. Description of Related Art
Nowadays, various construction machines including construction machines of the traveling type such as a hydraulic excavator, construction machines of the stationary type such as a crane, and so forth are used in various fields on construction sites, harbors, in factories and so forth. Construction machines are generally used in severe environments for excavation of rock at a dam, a tunnel, a river, a road or the like, for demolition of a building, a structure or the like, or for other objects. In such environments as just described, the load applied to a component apparatus such as an engine or a hydraulic pump is high, and a rise of the engine temperature or a rise of the temperature of operating oil is likely to occur. Therefore, such construction machines as mentioned above include a radiator and an oil cooler (hereinafter referred to generally as coolers) of a comparatively large capacity, and engine cooling water and operating oil are cooled by the coolers.
Conventionally, the coolers are disposed in series forwardly of the engine and cooled by cooling wind produced by a fan of the engine. However, where a plurality of coolers are arranged in a flow path of cooling wind in this manner, they disturb a flow of the cooling wind and lower the cooling efficiency. Particularly in recent years, not only a radiator and an oil cooler, but also other coolers such as an after cooler and an air condenser and apparatus other than coolers such as an air cleaner are disposed in a flow path of cooling wind, and the worry for a drop of the cooling efficiency is increasing more and more.
Therefore, in recent years, such a cooling package for a construction machine as shown in FIG. 10 has been proposed. The cooling package shown in FIG. 10 is for use with a hydraulic excavator, and the hydraulic excavator includes a lower traveling unit 1, an upper revolving unit 2 disposed for revolving movement on the upper side of the lower traveling unit 1, and a working apparatus 3 provided on the upper revolving unit 2 for carrying out various works. An engine 10 to which a hydraulic pump 11 is connected is disposed horizontally in a space between a cabin 4 provided at a front end portion of the upper revolving unit 2 and a counterweight 5 provided at a rear end portion of the upper revolving unit 2.
In the cooling package, a radiator 15 is disposed forwardly of a first fan 13 which is driven by the engine 10, and a second fan 14 and an oil cooler 16 driven by a motor 12 are disposed between the space in which the engine 10, fan 13 and radiator 15 are disposed and the cabin 4. Due to such a structure as just described, the radiator 3.5 is cooled by cooling wind flowing from an intake 17 formed forwardly and upwardly of the radiator 15 toward the first fan 13 while the oil cooler 16 is cooled separately by cooling wind flowing from another intake 18 formed forwardly and upwardly of the oil cooler 16 toward the second fan 14. By disposing the radiator 15 and the oil cooler 16 separately from each other in this manner, improvement of the cooling efficiency of them is achieved.
Incidentally, since a construction machine is used in such environments as described above, it cannot be avoided that foreign articles such as a cloud of dust are admitted into the inside together with cooling wind. Such foreign articles are caught by, stick to, and accumulate on the core of a cooler and then clog the cooler thereby dropping the cooling capacity of the cooler. Thus, a cooling package has been proposed and placed into practical use wherein a screen (filter) is disposed forwardly of a cooler such that admission of foreign articles into the cooler is prevented by the screen.
A cooling package which includes a screen requires periodical cleaning and/or replacement of the screen because foreign articles stick to and accumulate on the screen. Upon such cleaning or replacement, a removing and mounting operation of removing the screen from the cooler and mounting it back onto the cooler is required. However, for example, in a hydraulic excavator, removal and mounting of the screen are performed with a side door on a side face of the machine body kept open. In recent years, however, an apparatus such as an air cleaner is sometimes disposed in a flow path of cooling water due to restriction to a space for disposition, and where the location forwardly of the cooler is occupied by an apparatus in this manner, it is very difficult to open the aide door and remove or mount the screen to or from the location.
In the hydraulic excavator of the type wherein the radiator 15 and the oil cooler 16 are disposed separately from each other as described above, if a side door 21A shown in FIGS. 10 and 11 is opened, then the radiator 15 can be exposed through the opening for the side door 21A. However, if an obstacle such as the air cleaner 20 shown in FIG. 10 is present forwardly of the radiator 15, then it is difficult to remove or mount a screen of the radiator 15 through the opening with the side door 21A open. Therefore, in this instance, an engine hood 22 is opened and the screen is removed or mounted through the opening for the engine hood 22. While the engine hood 22 is provided to allow maintenance of the engine 10, where the range of coverage of the engine hood 22 is extended to a location above the radiator 15 as shown in FIGS. 10 and 11, the screen of the radiator 15 can be removed or mounted through the opening when the engine hood 22 is opened.
Meanwhile, although the oil cooler 16 can be exposed, if a side door 21B is opened, through an opening for the side door 21B, similarly as in the case of the radiator 15, where there is an obstacle forwardly of the oil cooler 16, it is difficult to remove or mount the screen of the oil cooler 16 through the opening with the side door 21B opened. Further, since also the engine hood 22 is not provided so as to cover even the oil cooler 16, it is impossible to remove or mount the screen of the oil cooler 16 through the opening when the engine hood 22 is opened.
The present invention has been made in view of such subjects as described above, and it is an object of the present invention to provide a cover structure for a cooling package of a construction machine wherein, where a cooler from among different coolers such as a radiator and an oil cooler is disposed separately from an engine and the separately disposed cooler includes a screen, even where a location forwardly of the separately disposed cooler is occupied by some other apparatus, the screen can be removed and mounted without being disturbed by such apparatus.